Fernanda do Canto Rothier

The understanding of the nanostructure of cosmetic products plays a crucial role in predicting their macroscopic and sensory properties, as structural features at the molecular scale directly influence product functionality and consumer perception. Despite this, there remains a significant gap in colloid physical chemistry knowledge within the cosmetic industry, which can limit the performance and innovation capacity of many professionals. The main objective of this study is to propose a classification of cosmetics as colloidal systems, through the detailed characterization of representative products from different classes, correlating their structures with rheological and textural properties. To achieve this, a comprehensive survey of commercial data and chemical composition was conducted, followed by experimental analyses using techniques such as microscopy, laser diffraction, texture analysis, and rheology. The results revealed a broad range of colloidal systems, including micellar solutions, emulsions, foams, suspensions, gels, aerosols, and liquid-crystalline phases. Cleansing systems exhibited low structural organization, whereas more structured systems, such as conditioners and shaving foam, displayed lamellar liquid-crystalline organization confirmed by SAXS and polarized microscopy. These systems showed enhanced viscoelasticity and mechanical strength. Quantitative correlations between nanoscale structure (e.g., micellar dimensions, lamellar periodicity, and particle size) and macroscopic properties (viscosity, viscoelasticity, and spreadability) were established. The results allowed the identification of the predominant colloidal class of each product, including micellar solutions, liquid crystals, emulsions, foams, suspensions, gels, and aerosols. This approach demonstrates how the macroscopic properties of cosmetic products emerge directly from their colloidal organization, providing a more fundamental understanding of formulation performance. Ultimately, this work contributes to offering formulators conceptual tools that enable more rational control over desired properties, fostering the development of more effective and
innovative cosmetic products.

Mestranda em Química | 2026